document.write( "Question 1092307: Find an for the arithmetic series
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Algebra.Com's Answer #706907 by Edwin McCravy(20056)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "\"S%5Bn%5D\"\"%22%22=%22%22\"\"expr%28n%2F2%29%282a%5B1%5D%2B%28n-1%29d%5E%22%22%29\"\r\n" );
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document.write( "Substitute n = 16, a1 = -21\r\n" );
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document.write( "\"S%5B16%5D\"\"%22%22=%22%22\"\"expr%2816%2F2%29%282%28-21%29%2B%2816-1%29d%5E%22%22%29\"\r\n" );
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document.write( "Substitute S16 = -288.\r\n" );
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document.write( "\"-288\"\"%22%22=%22%22\"\"%288%29%282%28-21%29%2B%2816-1%29d%5E%22%22%29\" \r\n" );
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document.write( "Now simplify that and solve for d.\r\n" );
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document.write( "When you find d, substitute it and a1 = -21\r\n" );
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document.write( "into \r\n" );
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document.write( "\"a%5Bn%5D\"\"%22%22=%22%22\"\"a%5B1%5D%2B%28n-1%29d\"\r\n" );
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document.write( "And simplify the right side:\r\n" );
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document.write( "You finish.\r\n" );
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document.write( "Edwin
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